Kalinin K-2

Kalinin K-2

[Despite the success of his first design, Konstantin Alexeyevich Kalinin devoted himself to improving it. Aware of its shortcomings and some of their causes, he decided to build an improved model. But in the meantime, he managed to experience one more major change. In mid-May 1926, the leadership of the VVS RKKA (VVS RKKA Directorate) issued K. A. Kalinin was ordered to create a new aviation plant in Kharkov (Харьков). Kalinin responded positively to the proposal to work in Kharkov, and together with him his closest associates move from Kiev to the new location, soon forming a small design team. Among them is I. R. Neman (И.Г. Неман), who later became a renowned aircraft designer himself. The first feat of the new KB was the construction of the K - 2 aircraft. But the repair plant was not an ideal environment for the work of a design bureau. Work was slow, the workshops were even busier with repair work than in previous years. In addition to the normal operational needs, the plant performed all kinds of overhauls of foreign-made aircraft. This led to tensions between KB and the workshop management, which culminated in September 1927. It turned out that it was impossible to combine both types of activities in a meaningful way in a single facility. Production capacities remained modest, and there was a lack of qualified specialists. That is why, on 17 September 1926, an order appeared on the official board of the administration building: "In view of the importance of the expanded activities of the aviation workshops, the development of their own aviation development and production, and their focus on the fulfillment of large orders, the aviation repair workshops of the UVP to date are to be renamed the Aircraft Factory of the Sovnarkom of the USSR (Авиазавод им. Thus, this date - 17 September 1926 - became the day of the birth of the Kharkiv Aviation Plant. K. A. Kalinin was appointed director and chief designer of the enterprise.


The start of aircraft construction in Kharkov was difficult: there was a lack of qualified workers, skilled workers. There was a shortage of materials, insufficient factory space and lack of funds. The designers were trying to create a versatile and production-economical aircraft that would offer the possibility of carrying three passengers with a crew of two. In addition to passenger, it also handled medical and photographic variants.


The new machine was a development of the original K-1. The main change was an all-metal fuselage and wing construction and a new engine - BMW-IV with 240 hp. The machine was built in 4 pieces.


In basic scheme and actual outlines, the K-2 is almost indistinguishable from the K-1, but the similarity is only external. The new plane was without the wooden elements. The airframe was made of fine steel tubes using gas welding. The passenger cabin cover was made of finely corrugated sheets of kolchugaljuminum. The same technology was used to create the wing and tail surfaces. As with the previous machine, the wing was regularly elliptical in plan. The wing spar and rib were made of colchugaluminum, the wing and tail surfaces were covered with a particularly strong and light canvas. The more powerful engine of the BMV-IV made it possible to increase the overall payload and increase the number of passengers to four.


On the sunny morning of 12 May 1927, the first take-off of the new K-2 took place at the Kharkov airfield. Robitnik Sičnevki(Robiтник Сiчневки). The test confirmed both the functional reliability and the non-intrusiveness of the machine. At the same time, it was clear to Kalinin that the all-metal construction proved rather heavy and non-technological, and above all expensive. Nevertheless, the K-2 successfully passed the tests, flying a total of 129 hours without accidents during the 1927 autumn flying season. The company concluded the tests with a final evaluation by the test pilot: the entire front fuselage was coated with duralumin, the landing gear struts were covered with a canvas aerodynamic cover, an additional gasoline tank was added, and the keel and rudder design were substantially changed.

The K-2 was then successfully used for aerial photography and mapping of many areas of the country.

ru.wikipedia.org
http://airwar.ru/enc/cw1/k2.html
www.aeronautics.ru
http://focus.in.ua/article/history/10848.html